This carts works very well for our double ocean rowing shell (about 120 lb. fully rigged) -- it's easy to get the boat on and off, easy rolling on smooth surfaces, etc.
However, the wheels don't have bearings. Their inner shell rotates directly on the aluminum strut (which acts like an axle) of the dolly. Over time, the wheel wears through the strut, and the dolly is ruined. (You can't buy a replacement strut.) This happened to ours after about 220 launches off a sandy beach (The sand greatly increases the wear. If you launch off a rocky beach, you'll probably get much longer life.)I got my cart several years ago and found it to be great for the canoe and kayak transport but too bulky to put in my kayak. The cart has made transporting the canoe and kayak a breeze and opens up a new realm of possibility for many people who cannot move canoes and kayaks to water even a short distance. Even a large canoe or kayak can be moved by a 10 year old long distances with ease. And with a special attachment over all types of terrain.
I have gone over the weight rating for short distances but don't recommend it as it can damage the tires, especially if they are partially inflated. Once move a small log out of the way that was hard to pick up. The cart requires straps, rope or bungy cord to hold the boat on to the cart. I use a bungy cord on hard surfaces without obstacles, but straps are better as they hold the boat on tighter, especially in rough terrain. I have pulled my boat off the cart when I am not careful about tightening the bungies.
The biggest problems I have had were with the wheels; though not a serious problem. The tires can become deflated over time develop leaks. You can ruin a tire but using deflated or partially deflated tires. I have been told by a dealer that a bike air installed fix a flat mixture will eliminate many of the problems with small leaks. Fixing a flat is difficult as the tires do not easily come off the rims. The softer cart tires are hard to come by locally and very difficult to change because the wheel rim does not come apart. Standard hand truck tires tend to be structurally inflexible - making it all but impossible to get the hand truck tires on the rims.
The manufacturer told me that they discontinued the wheels assemblies that came apart because they were weaker structurally. A legitimate trade off. The cheapest way to deal with bad tires it to order new wheel and tire assemblies from Roleez. They charge 15 dollars per wheel assembly which is cheaper than the tube and tire from a hand truck dealer. The wheels should last for over 10 years or more with proper care.